Annotation of ircnowd/src/ngircd/parse.c, Revision 1.1.1.1
1.1 tomglok 1: /*
2: * ngIRCd -- The Next Generation IRC Daemon
3: * Copyright (c)2001-2018 Alexander Barton (alex@barton.de) and Contributors.
4: *
5: * This program is free software; you can redistribute it and/or modify
6: * it under the terms of the GNU General Public License as published by
7: * the Free Software Foundation; either version 2 of the License, or
8: * (at your option) any later version.
9: * Please read the file COPYING, README and AUTHORS for more information.
10: */
11:
12: #include "portab.h"
13:
14: /**
15: * @file
16: * IRC command parser and validator.
17: */
18:
19: #include <assert.h>
20: #include <stdlib.h>
21: #include <string.h>
22: #include <strings.h>
23:
24: #include "ngircd.h"
25: #include "conn-func.h"
26: #include "conf.h"
27: #include "channel.h"
28: #include "log.h"
29: #include "messages.h"
30:
31: #include "parse.h"
32:
33: #include "irc.h"
34: #include "irc-cap.h"
35: #include "irc-channel.h"
36: #ifdef ICONV
37: # include "irc-encoding.h"
38: #endif
39: #include "irc-info.h"
40: #include "irc-login.h"
41: #include "irc-metadata.h"
42: #include "irc-mode.h"
43: #include "irc-op.h"
44: #include "irc-oper.h"
45: #include "irc-server.h"
46: #include "irc-write.h"
47: #include "numeric.h"
48:
49: struct _NUMERIC {
50: int numeric;
51: bool (*function) PARAMS(( CLIENT *Client, REQUEST *Request ));
52: };
53:
54:
55: static COMMAND My_Commands[] =
56: {
57: #define _CMD(name, func, type, min, max, penalty) \
58: { (name), (func), (type), (min), (max), (penalty), 0, 0, 0 }
59: _CMD("ADMIN", IRC_ADMIN, CLIENT_USER|CLIENT_SERVER, 0, 1, 1),
60: _CMD("AWAY", IRC_AWAY, CLIENT_USER, 0, 1, 0),
61: _CMD("CAP", IRC_CAP, CLIENT_ANY, 1, 2, 0),
62: _CMD("CONNECT", IRC_CONNECT, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
63: #ifdef STRICT_RFC
64: _CMD("DIE", IRC_DIE, CLIENT_USER, 0, 0, 0),
65: #else
66: _CMD("DIE", IRC_DIE, CLIENT_USER, 0, 1, 0),
67: #endif
68: _CMD("DISCONNECT", IRC_DISCONNECT, CLIENT_USER, 1, 1, 0),
69: _CMD("ERROR", IRC_ERROR, CLIENT_ANY, 0, -1, 0),
70: _CMD("GLINE", IRC_xLINE, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
71: _CMD("HELP", IRC_HELP, CLIENT_USER, 0, 1, 2),
72: _CMD("INFO", IRC_INFO, CLIENT_USER|CLIENT_SERVER, 0, 1, 2),
73: _CMD("INVITE", IRC_INVITE, CLIENT_USER|CLIENT_SERVER, 2, 2, 1),
74: _CMD("ISON", IRC_ISON, CLIENT_USER, 1, -1, 0),
75: _CMD("JOIN", IRC_JOIN, CLIENT_USER|CLIENT_SERVER, 1, 2, 0),
76: _CMD("KICK", IRC_KICK, CLIENT_USER|CLIENT_SERVER, 2, 3, 0),
77: _CMD("KILL", IRC_KILL, CLIENT_USER|CLIENT_SERVER, 2, 2, 0),
78: _CMD("KLINE", IRC_xLINE, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
79: _CMD("LINKS", IRC_LINKS, CLIENT_USER|CLIENT_SERVER, 0, 2, 1),
80: _CMD("LIST", IRC_LIST, CLIENT_USER|CLIENT_SERVER, 0, 2, 2),
81: _CMD("LUSERS", IRC_LUSERS, CLIENT_USER|CLIENT_SERVER, 0, 2, 1),
82: _CMD("METADATA", IRC_METADATA, CLIENT_SERVER, 3, 3, 0),
83: _CMD("MODE", IRC_MODE, CLIENT_USER|CLIENT_SERVER, 1, -1, 1),
84: _CMD("MOTD", IRC_MOTD, CLIENT_USER|CLIENT_SERVER, 0, 1, 3),
85: _CMD("NAMES", IRC_NAMES, CLIENT_USER|CLIENT_SERVER, 0, 2, 1),
86: _CMD("NICK", IRC_NICK, CLIENT_ANY, 0, -1, 0),
87: _CMD("NJOIN", IRC_NJOIN, CLIENT_SERVER, 2, 2, 0),
88: _CMD("NOTICE", IRC_NOTICE, CLIENT_ANY, 0, -1, 0),
89: _CMD("OPER", IRC_OPER, CLIENT_USER, 2, 2, 0),
90: _CMD("PART", IRC_PART, CLIENT_USER|CLIENT_SERVER, 1, 2, 0),
91: _CMD("PASS", IRC_PASS, CLIENT_ANY, 0, -1, 0),
92: _CMD("PING", IRC_PING, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
93: _CMD("PONG", IRC_PONG, CLIENT_ANY, 0, -1, 0),
94: _CMD("PRIVMSG", IRC_PRIVMSG, CLIENT_USER|CLIENT_SERVER, 0, 2, 0),
95: _CMD("QUIT", IRC_QUIT, CLIENT_ANY, 0, 1, 0),
96: _CMD("REHASH", IRC_REHASH, CLIENT_USER, 0, 0, 0),
97: _CMD("RESTART", IRC_RESTART, CLIENT_USER, 0, 0, 0),
98: _CMD("SERVER", IRC_SERVER, CLIENT_ANY, 0, -1, 0),
99: _CMD("SERVICE", IRC_SERVICE, CLIENT_ANY, 6, 6, 0),
100: _CMD("SERVLIST", IRC_SERVLIST, CLIENT_USER, 0, 2, 1),
101: _CMD("SQUERY", IRC_SQUERY, CLIENT_USER|CLIENT_SERVER, 0, 2, 0),
102: _CMD("SQUIT", IRC_SQUIT, CLIENT_USER|CLIENT_SERVER, 2, 2, 0),
103: _CMD("STATS", IRC_STATS, CLIENT_USER|CLIENT_SERVER, 0, 2, 2),
104: _CMD("SVSNICK", IRC_SVSNICK, CLIENT_SERVER, 2, 2, 0),
105: _CMD("SUMMON", IRC_SUMMON, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
106: _CMD("TIME", IRC_TIME, CLIENT_USER|CLIENT_SERVER, 0, 1, 1),
107: _CMD("TOPIC", IRC_TOPIC, CLIENT_USER|CLIENT_SERVER, 1, 2, 1),
108: _CMD("TRACE", IRC_TRACE, CLIENT_USER|CLIENT_SERVER, 0, 1, 3),
109: _CMD("USER", IRC_USER, CLIENT_ANY, 0, -1, 0),
110: _CMD("USERHOST", IRC_USERHOST, CLIENT_USER, 1, -1, 1),
111: _CMD("USERS", IRC_USERS, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
112: _CMD("VERSION", IRC_VERSION, CLIENT_USER|CLIENT_SERVER, 0, 1, 1),
113: _CMD("WALLOPS", IRC_WALLOPS, CLIENT_USER|CLIENT_SERVER, 1, 1, 0),
114: _CMD("WEBIRC", IRC_WEBIRC, CLIENT_UNKNOWN, 4, 5, 0),
115: _CMD("WHO", IRC_WHO, CLIENT_USER, 0, 2, 1),
116: _CMD("WHOIS", IRC_WHOIS, CLIENT_USER|CLIENT_SERVER, 0, -1, 1),
117: _CMD("WHOWAS", IRC_WHOWAS, CLIENT_USER|CLIENT_SERVER, 0, -1, 0),
118:
119: #ifdef IRCPLUS
120: _CMD("CHANINFO", IRC_CHANINFO, CLIENT_SERVER, 0, -1, 0),
121: # ifdef ICONV
122: _CMD("CHARCONV", IRC_CHARCONV, CLIENT_USER, 1, 1, 0),
123: # endif
124: #endif
125:
126: #ifndef STRICT_RFC
127: _CMD("GET", IRC_QUIT_HTTP, CLIENT_UNKNOWN, 0, -1, 0),
128: _CMD("POST", IRC_QUIT_HTTP, CLIENT_UNKNOWN, 0, -1, 0),
129: #endif
130: _CMD(NULL, NULL, 0, 0, 0, 0) /* End-Mark */
131: #undef _CMD
132: };
133:
134: static void Init_Request PARAMS(( REQUEST *Req ));
135:
136: static bool Validate_Prefix PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
137: static bool Validate_Command PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
138: static bool Validate_Args PARAMS(( CONN_ID Idx, REQUEST *Req, bool *Closed ));
139:
140: static bool Handle_Request PARAMS(( CONN_ID Idx, REQUEST *Req ));
141:
142: static bool ScrubCTCP PARAMS((char *Request));
143:
144: /**
145: * Return the pointer to the global "IRC command structure".
146: * This structure, an array of type "COMMAND" describes all the IRC commands
147: * implemented by ngIRCd and how to handle them.
148: * @return Pointer to the global command structure.
149: */
150: GLOBAL COMMAND *
151: Parse_GetCommandStruct( void )
152: {
153: return My_Commands;
154: } /* Parse_GetCommandStruct */
155:
156:
157: /**
158: * Parse a command ("request") received from a client.
159: *
160: * This function is called after the connection layer received a valid CR+LF
161: * terminated line of text: we assume that this is a valid IRC command and
162: * try to do something useful with it :-)
163: *
164: * All errors are reported to the client from which the command has been
165: * received, and if the error is fatal this connection is closed down.
166: *
167: * This function is able to parse the syntax as described in RFC 2812,
168: * section 2.3.
169: *
170: * @param Idx Index of the connection from which the command has been received.
171: * @param Request NULL terminated line of text (the "command").
172: * @return CONNECTED on success (valid command or "regular" error), DISCONNECTED
173: * if a fatal error occurred and the connection has been shut down.
174: */
175: GLOBAL bool
176: Parse_Request( CONN_ID Idx, char *Request )
177: {
178: REQUEST req;
179: char *start, *ptr;
180: bool closed;
181:
182: assert( Idx >= 0 );
183: assert( Request != NULL );
184:
185: #ifdef SNIFFER
186: if( NGIRCd_Sniffer ) Log( LOG_DEBUG, " <- connection %d: '%s'.", Idx, Request );
187: #endif
188:
189: Init_Request( &req );
190:
191: /* remove leading & trailing whitespace */
192: ngt_TrimStr( Request );
193:
194: if (Conf_ScrubCTCP && ScrubCTCP(Request))
195: return true;
196:
197: if (Request[0] == ':') {
198: /* Prefix */
199: req.prefix = Request + 1;
200: ptr = strchr( Request, ' ' );
201: if( ! ptr )
202: {
203: LogDebug("Connection %d: Parse error: prefix without command!?", Idx);
204: return Conn_WriteStr(Idx, "ERROR :Prefix without command");
205: }
206: *ptr = '\0';
207: #ifndef STRICT_RFC
208: /* ignore multiple spaces between prefix and command */
209: while( *(ptr + 1) == ' ' ) ptr++;
210: #endif
211: start = ptr + 1;
212: }
213: else start = Request;
214:
215: ptr = strchr( start, ' ' );
216: if( ptr )
217: {
218: *ptr = '\0';
219: #ifndef STRICT_RFC
220: /* ignore multiple spaces between parameters */
221: while( *(ptr + 1) == ' ' ) ptr++;
222: #endif
223: }
224: req.command = start;
225:
226: /* Arguments, Parameters */
227: if( ptr )
228: {
229: start = ptr + 1;
230: while( start )
231: {
232: if( start[0] == ':' )
233: {
234: req.argv[req.argc] = start + 1;
235: ptr = NULL;
236: }
237: else
238: {
239: req.argv[req.argc] = start;
240: ptr = strchr( start, ' ' );
241: if( ptr )
242: {
243: *ptr = '\0';
244: #ifndef STRICT_RFC
245: while( *(ptr + 1) == ' ' ) ptr++;
246: #endif
247: }
248: }
249:
250: req.argc++;
251:
252: if( start[0] == ':' ) break;
253: if( req.argc > 14 ) break;
254:
255: if( ptr ) start = ptr + 1;
256: else start = NULL;
257: }
258: }
259:
260: if(!Validate_Prefix(Idx, &req, &closed))
261: return !closed;
262: if(!Validate_Command(Idx, &req, &closed))
263: return !closed;
264: if(!Validate_Args(Idx, &req, &closed))
265: return !closed;
266:
267: return Handle_Request(Idx, &req);
268: } /* Parse_Request */
269:
270:
271: /**
272: * Initialize request structure.
273: * @param Req Request structure to be initialized.
274: */
275: static void
276: Init_Request( REQUEST *Req )
277: {
278: int i;
279:
280: assert( Req != NULL );
281:
282: Req->prefix = NULL;
283: Req->command = NULL;
284: for( i = 0; i < 15; Req->argv[i++] = NULL );
285: Req->argc = 0;
286: } /* Init_Request */
287:
288:
289: static bool
290: Validate_Prefix( CONN_ID Idx, REQUEST *Req, bool *Closed )
291: {
292: CLIENT *client, *c;
293:
294: assert( Idx >= 0 );
295: assert( Req != NULL );
296:
297: *Closed = false;
298:
299: client = Conn_GetClient( Idx );
300: assert( client != NULL );
301:
302: if (!Req->prefix && Client_Type(client) == CLIENT_SERVER
303: && !(Conn_Options(Idx) & CONN_RFC1459)
304: && strcasecmp(Req->command, "ERROR") != 0
305: && strcasecmp(Req->command, "PING") != 0)
306: {
307: Log(LOG_ERR,
308: "Received command without prefix (connection %d, command \"%s\")!?",
309: Idx, Req->command);
310: if (!Conn_WriteStr(Idx, "ERROR :Prefix missing"))
311: *Closed = true;
312: return false;
313: }
314:
315: if (!Req->prefix)
316: return true;
317:
318: /* only validate if this connection is already registered */
319: if (Client_Type(client) != CLIENT_USER
320: && Client_Type(client) != CLIENT_SERVER
321: && Client_Type(client) != CLIENT_SERVICE) {
322: /* not registered, ignore prefix */
323: Req->prefix = NULL;
324: return true;
325: }
326:
327: /* check if client in prefix is known */
328: c = Client_Search(Req->prefix);
329: if (!c) {
330: if (Client_Type(client) != CLIENT_SERVER) {
331: Log(LOG_ERR,
332: "Ignoring command with invalid prefix \"%s\" from \"%s\" (connection %d, command \"%s\")!",
333: Req->prefix, Client_ID(client), Idx, Req->command);
334: if (!Conn_WriteStr(Idx,
335: "ERROR :Invalid prefix \"%s\"",
336: Req->prefix))
337: *Closed = true;
338: IRC_SetPenalty(client, 2);
339: } else
340: LogDebug("Ignoring command with invalid prefix \"%s\" from \"%s\" (connection %d, command \"%s\")!",
341: Req->prefix, Client_ID(client), Idx, Req->command);
342: return false;
343: }
344:
345: /* check if the client named in the prefix is expected
346: * to come from that direction */
347: if (Client_NextHop(c) != client) {
348: if (Client_Type(client) != CLIENT_SERVER) {
349: Log(LOG_ERR,
350: "Spoofed prefix \"%s\" from \"%s\" (connection %d, command \"%s\"), closing connection!",
351: Req->prefix, Client_ID(client), Idx, Req->command);
352: Conn_Close(Idx, NULL, "Spoofed prefix", true);
353: *Closed = true;
354: } else {
355: Log(LOG_WARNING,
356: "Ignoring command with spoofed prefix \"%s\" from \"%s\" (connection %d, command \"%s\")!",
357: Req->prefix, Client_ID(client), Idx, Req->command);
358: }
359: return false;
360: }
361:
362: return true;
363: } /* Validate_Prefix */
364:
365:
366: static bool
367: Validate_Command( UNUSED CONN_ID Idx, UNUSED REQUEST *Req, bool *Closed )
368: {
369: assert( Idx >= 0 );
370: assert( Req != NULL );
371: *Closed = false;
372:
373: return true;
374: } /* Validate_Command */
375:
376:
377: static bool
378: #ifdef STRICT_RFC
379: Validate_Args(CONN_ID Idx, REQUEST *Req, bool *Closed)
380: #else
381: Validate_Args(UNUSED CONN_ID Idx, UNUSED REQUEST *Req, bool *Closed)
382: #endif
383: {
384: #ifdef STRICT_RFC
385: int i;
386: #endif
387:
388: *Closed = false;
389:
390: #ifdef STRICT_RFC
391: assert( Idx >= 0 );
392: assert( Req != NULL );
393:
394: /* CR and LF are never allowed in command parameters.
395: * But since we do accept lines terminated only with CR or LF in
396: * "non-RFC-compliant mode" (besides the correct CR+LF combination),
397: * this check can only trigger in "strict RFC" mode; therefore we
398: * optimize it away otherwise ... */
399: for (i = 0; i < Req->argc; i++) {
400: if (strchr(Req->argv[i], '\r') || strchr(Req->argv[i], '\n')) {
401: Log(LOG_ERR,
402: "Invalid character(s) in parameter (connection %d, command %s)!?",
403: Idx, Req->command);
404: if (!Conn_WriteStr(Idx,
405: "ERROR :Invalid character(s) in parameter!"))
406: *Closed = true;
407: return false;
408: }
409: }
410: #endif
411:
412: return true;
413: } /* Validate_Args */
414:
415:
416: /* Command is a status code ("numeric") from another server */
417: static bool
418: Handle_Numeric(CLIENT *client, REQUEST *Req)
419: {
420: static const struct _NUMERIC Numerics[] = {
421: { 5, IRC_Num_ISUPPORT },
422: { 20, NULL },
423: { 376, IRC_Num_ENDOFMOTD }
424: };
425: int i, num;
426: char str[COMMAND_LEN];
427: CLIENT *prefix, *target = NULL;
428:
429: /* Determine target */
430: if (Req->argc > 0) {
431: if (strcmp(Req->argv[0], "*") != 0)
432: target = Client_Search(Req->argv[0]);
433: else
434: target = Client_ThisServer();
435: }
436:
437: if (!target) {
438: /* Status code without target!? */
439: if (Req->argc > 0)
440: Log(LOG_WARNING,
441: "Unknown target for status code %s: \"%s\"",
442: Req->command, Req->argv[0]);
443: else
444: Log(LOG_WARNING,
445: "Unknown target for status code %s!",
446: Req->command);
447: return true;
448: }
449: if (target == Client_ThisServer()) {
450: /* This server is the target of the numeric */
451: num = atoi(Req->command);
452:
453: for (i = 0; i < (int) C_ARRAY_SIZE(Numerics); i++) {
454: if (num == Numerics[i].numeric) {
455: if (!Numerics[i].function)
456: return CONNECTED;
457: return Numerics[i].function(client, Req);
458: }
459: }
460:
461: LogDebug("Ignored status code %s from \"%s\".",
462: Req->command, Client_ID(client));
463: return true;
464: }
465:
466: /* Determine source */
467: if (!Req->prefix) {
468: Log(LOG_WARNING,
469: "Got status code %s from \"%s\" without prefix!?",
470: Req->command, Client_ID(client));
471: return true;
472: }
473:
474: prefix = Client_Search(Req->prefix);
475: if (! prefix) { /* Oops, unknown prefix!? */
476: Log(LOG_WARNING, "Got status code %s from unknown source: \"%s\"", Req->command, Req->prefix);
477: return true;
478: }
479:
480: /* Forward status code */
481: strlcpy(str, Req->command, sizeof(str));
482: for (i = 0; i < Req->argc; i++) {
483: if (i < Req->argc - 1)
484: strlcat(str, " ", sizeof(str));
485: else
486: strlcat(str, " :", sizeof(str));
487: strlcat(str, Req->argv[i], sizeof(str));
488: }
489: return IRC_WriteStrClientPrefix(target, prefix, "%s", str);
490: }
491:
492: static bool
493: Handle_Request( CONN_ID Idx, REQUEST *Req )
494: {
495: CLIENT *client;
496: bool result = CONNECTED;
497: int client_type;
498: COMMAND *cmd;
499:
500: assert( Idx >= 0 );
501: assert( Req != NULL );
502: assert( Req->command != NULL );
503:
504: client = Conn_GetClient( Idx );
505: assert( client != NULL );
506:
507: /* Numeric? */
508: client_type = Client_Type(client);
509: if ((client_type == CLIENT_SERVER ||
510: client_type == CLIENT_UNKNOWNSERVER)
511: && strlen(Req->command) == 3 && atoi(Req->command) > 1)
512: return Handle_Numeric(client, Req);
513:
514: cmd = My_Commands;
515: while (cmd->name) {
516: if (strcasecmp(Req->command, cmd->name) != 0) {
517: cmd++;
518: continue;
519: }
520:
521: if (!(client_type & cmd->type)) {
522: if (client_type == CLIENT_USER
523: && cmd->type & CLIENT_SERVER)
524: return IRC_WriteErrClient(client,
525: ERR_NOTREGISTEREDSERVER_MSG,
526: Client_ID(client));
527: else
528: return IRC_WriteErrClient(client,
529: ERR_NOTREGISTERED_MSG,
530: Client_ID(client));
531: }
532:
533: if (cmd->penalty)
534: IRC_SetPenalty(client, cmd->penalty);
535:
536: if (Req->argc < cmd->min_argc ||
537: (cmd->max_argc != -1 && Req->argc > cmd->max_argc))
538: return IRC_WriteErrClient(client, ERR_NEEDMOREPARAMS_MSG,
539: Client_ID(client), Req->command);
540:
541: /* Command is allowed for this client: call it and count
542: * generated bytes in output */
543: Conn_ResetWCounter();
544: result = (cmd->function)(client, Req);
545: cmd->bytes += Conn_WCounter();
546:
547: /* Adjust counters */
548: if (client_type != CLIENT_SERVER)
549: cmd->lcount++;
550: else
551: cmd->rcount++;
552:
553: /* Return result of command (CONNECTED/DISCONNECTED). */
554: return result;
555: }
556:
557: if (client_type != CLIENT_USER &&
558: client_type != CLIENT_SERVER &&
559: client_type != CLIENT_SERVICE )
560: return true;
561:
562: LogDebug("Connection %d: Unknown command \"%s\", %d %s,%s prefix.",
563: Client_Conn( client ), Req->command, Req->argc,
564: Req->argc == 1 ? "parameter" : "parameters",
565: Req->prefix ? "" : " no" );
566:
567: /* Unknown command and registered connection: generate error: */
568: if (client_type != CLIENT_SERVER)
569: result = IRC_WriteErrClient(client, ERR_UNKNOWNCOMMAND_MSG,
570: Client_ID(client), Req->command);
571:
572: return result;
573: } /* Handle_Request */
574:
575:
576: /**
577: * Check if incoming messages contains CTCP commands and should be dropped.
578: *
579: * @param Request NULL terminated incoming command.
580: * @returns true, when the message should be dropped.
581: */
582: static bool
583: ScrubCTCP(char *Request)
584: {
585: static const char me_cmd[] = "ACTION ";
586: static const char ctcp_char = 0x1;
587: bool dropCommand = false;
588: char *ptr = Request;
589: char *ptrEnd = strchr(Request, '\0');
590:
591: if (Request[0] == ':' && ptrEnd > ptr)
592: ptr++;
593:
594: while (ptr != ptrEnd && *ptr != ':')
595: ptr++;
596:
597: if ((ptrEnd - ptr) > 1) {
598: ptr++;
599: if (*ptr == ctcp_char) {
600: dropCommand = true;
601: ptr++;
602: /* allow /me commands */
603: if ((size_t)(ptrEnd - ptr) >= strlen(me_cmd)
604: && !strncmp(ptr, me_cmd, strlen(me_cmd)))
605: dropCommand = false;
606: }
607: }
608: return dropCommand;
609: }
610:
611: /* -eof- */
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